Arc interrupter



Patented 14, 1933 PATENT,4 OFFICEv RALPH 2R.. PITTMAN, PINE BLUFF,ARKANSAS ARC INTEBBUPTER Application led September 12, y1930. Serial No.481,437.

This invention relates to means for protectingelectrical power andtransmission lines and /or apparatus connected thereto by draining lfromthe line and/or apparatus high 5 superimposed voltages andtheirattendant currents, such as may be caused by lightning y,

i '.g Another object is-the provision of a novel lconstruction of an arcinterrupter for use in connection with electrical transmission linesand/or` apparatus connected thereto, and a further object is theprovision'of means for .l indicating after each operation the conditionof the arcing n .In-the drawing y Figure 1 is an elevation of atransmission line supporting tower with the arc interrupter arrangement;mounted thereon inservice vposition. l i

Figure 2 is an elevationyof'an arc interrupter as constructed inaccordance with the invention. f .v

Figure 3 is a vertical section through the interrupter. .f i

The present construction possesses certain lgeneral features in commonVwith'those de scribed. in the applications abovementioned,

and includes a fibrous insulating tube 18Y grounded at 16 from fa lowerelectrode 22. -A top electrode 21 is supported'in place by a metalconnecting plug 24 which entirely closes the openinof the tube, and issecured rigidly in place y a metal band 25. VThe f 'metal band 25entirely encircles the insulating tube 18 and is tightly clampedthereon, thus holding the plug 24 and electrode 21 rigidly in place.`v Aweather-proof metal cap 19vis electrically connected by a fusibleelement 23 to the metal conducting plug 24. The fusible 5o element 23 isattached by any suitable means,

chamber of the arc interrupter.

not shown, to the metal cap 19 and metal plug 24. Soldering vhas beenfound a suitable means in case copper wire is used as the fusibleelement.

In the drawing, Figurel illustrates a tower carrying three transmissionline conductors 10 such as may be used in a three-phase transmissionline.

In accordance with the usual practice, these conductors are suspendedfrom suspension 00 insulators 11 depending from a wooden crossy arm 12,which connects the tops of the tower poles 13, which poles are suitablyanchored in the ground at their bases 14' andare provided throughouttheir-entire lengths with ground .65 wires 15 which rare well groundedas indicated at the points 16. l In vertically lspaced relation below!the transmission line conductors 10, lthe oles 13 are provided with ametal cross arm 1 which 70 is of metal construction throughout and whichis secured to the poles in positive electrical contactv with the groundwires 15.

On the metal cross arm 17 are detachably )mounted at spaced intervalsvertically below the respective transmission `line conductors, a seriesof arc interrupters 18', Vone of whichl is illustrated in detail inFigures 2 and 3, all of the interrupters being identical inconstruction.

In operation, any extraneous voltage S-uperimposed on a conductor 1Q,which is of sufficient value will cause a current to flow from thisconductorlO to the weather-proof capv19 through the fusible element23-'to the.,85 conducting plug 24; from the conducting plu v 24 to theelectrode 21 and thence to groun 16, through the fibrous insulating tube18, the vlower electrode 22 and theV ound wire 15. In this manner, anarc is estalrished from the conductorlO to theweather-proof cap 19 andwithin the arc interrupter` f -rdm the electrode v 21 to theelectrodev22. The distance within y the fibrous insulating tube from thetop electrode 21 to the lower electrode 22 is purposely 95 made lessthan is the distance from the weather-proof cap 19 to the lowerelectrode 22, and thus the discharge naturally follows the path insidethe tube. Q A

Immediately following the drainage of the 10 extraneous current causedby the superimosed voltage, dynamic arcs are established between theconductor 10 and/ or its supporting clamp and weather-proof cap 19 andalso between the top electrode 21 andthe lower electrode 22 withinthefibrous insulating tube vextinguishing the resulting arc so that therewill be no interruption to service-over the transmission lines.

Inasmuch as the extinguishment of the arc is caused by the action of thearc on the material forming the inside walls of the arcing chamberthrough the generation of gas, it will be apparent that after successiveoperations the inner walls of the fibrous insulating tube formin thearcing chamber will be eventually so a ected by the high temperature ofsuccessive arcsas to cause a reduction in the quantity ofV gasygenerated and hence in the velocity of its expulsion from the arcingchamber. When such a condition obtains, the dynamic'current flowwillcontinue for a sufficient length of time to destroy the fusibleelement. 23, thus inserting inthe circuit to ground an additional lengthof fibrous tube and extinguishing the arc by this means.

Since the metal conductin plug 24 is rigidly secured in place in the tue, the gas formed upon the fusing ofthe element 23 is of sufficientpressure to remove the weather-proof cap 19, thus venting the gasesformed in the upper portion ofthe arc interrupter and at the same .timegiving positive visual indicap tion that the arc interrupter has beenrendered unfit for further service as such.

I nasmuch as the temperature` to which the fuslble element 23 issubjected is a function of also of the length of time the said currentflows through the fusible element, it will be seen that the fusibleelement 23 will not be destroyed until the inside wall of the fibrousmsulating tube 18 is so affected that the not only the magnitude of thecurrent, buttube, a removable metal ca kmerece .n 1. In an arcinterrupter, the combination of a hollow tube of insulating material, ametal cap disposed over one end of said tube and forming an electrode, ametal plug rigidly secured to the tube at a considerable distance thetherein and entirely closing the opening of i the tube, a fusibleelement connecting said cap with said plug, and a metal tube forming athird electrode in spaced relation to said plug within the tube.

2. In an l.arc interrupter, the combination of a hollow tube of fibrousinsulating material, a metal cap disposed over one end of said tube andforming an electrode, a metal plug rigidly secured to the tube at aconsiderable distance therein and entirely closing the opening of thetube,'a fusible element connecting said cap with said plug, and a thirdmetal electrode in spaced relation to said plug within the tube.

3. In an arc interrupter, the combination of a hollow tube of4insulating material, a removable metal cap disposed over one end of saidtube and forming an electrode, a metal plug'rigidly secured .to the tubeat-a considerable distance therein and entirely closing the opening ofthe tube, a fusible element connecting said removable cap with saidplug, and a metal tube forming a't'hird electrode in spaced'relation tosaid plug within the tube.

of an insulating tube o material adapted for volatilizing on theoccurrence of p an arc whereby to extinguish the arc` and expel gasesfrom the open end of the tube, a metal cap disposed over one end of saidtube and forming an electrode, a metal plug rigidly secured to thetubeat a considerable distance therein and entirely closing the openingof the, tube, a fusible element connecting saidecap with said plug, anda metal tube forming a third electrode in spaced relation to said plugwithin the tube.

5. In an arc interrupter, the combination of a hollow tube of fibrousinsulating material, said'material being adapted foi volatilizing on theoccurrence of an arc whereby'to extinguish the arc and expel gases fromthe disposed over 4. In an arc interrupter, the combination one end ofsaid tube and forming an electrode,

a metal plug rigidly secured a considerable necting said removable capwith said plug, and a, grounded metal tube forming a third electrode inspaced relation to said plug within the tube.

6. In anv arc interrupter, the combination of a ,hollow tube ofinsulating material, a metal electrode closing one endof the tube, ametal plug rigidly secured to the tube at a considerable distancetherein and entirely closing the opening of the tube, a fusible elementconnecting said electrode with said plug, and another electrode inspaced relation to said plug within the tube, there being materialbetween said plug and the latter electrode adapted for volatilizing uponexposure to an arc to extinguish the are and expel gases rom the openend of the tube.

In testimony whereof I af'x my signature.

RALPH R. PITTMAN.

